Apparatus for cooling under ultraviolet radiation and vacuum conditions



Aug. 19, 1947. w. L. MAXSON 2,425,816

APPARATUS FOR COOLING UNDER ULTRA VIOLET RADIATION AND VACUUM CONDITIONS Filed July 15, 1944 5 Sheets-Sheet 1 INVEN TOR.

By (11L. Maxison 1 7 6w Aug. 19, 1947. w. L. MAXSON 2,425,816

APPARATUS FOR COOLING UNDER ULTRA VIOLET RADIATION AND VACUUM CONDITIONS Filed July 13, 1944 5 Sheets-Sheet 2 uiu/ s IN V EN TOR.

BY ldLMclMson WIMQQ/rl 5w *5 Aug. 19, 1947. w. MAXSON 2,425,816

APPARATUS FOR CQOLING UNDER ULTRA VIOLET RADIATION AND VACUUM CONDITIONS Filed July 13, 1944 5 Sheets-Sheet 3 IN V EN TOR.

BY ZdL .Ma2690n 74m M 514/17.

Patented Aug. 19, 1947 z;425,s16 FFlCE APPARATUS FOR COOLING UNDER ULTRA- VIOLET RADIATION AND VACUUM CON- DITIONS William L. Manson, West Orange, N. J., assignor to The W. L. Manson Corporation, New York, N. Y., a corporation oi New York Application July 1:, 1944, Serial No. 544,785

6 Claims. 1

This invention relates to'a method of and apparatus for storage and-preservation of perishable materials such as foods. 4

This application is an improvement on the apparatus and method disclosed, in my application, Serial No. 534,902 and in addition to the evacuated refrigerated chamber disclosed in that application, in this invention I provide a germicidal lamp to sterilize the material stored within the chamber.

It is well known that four of the basic factors aiIecting storage of perishable materials, such as food, arebacteria, molds, dehydration and oxidation or respiration.

In the prior application 'I provide means for preventing dehydrationand oxidation, inhibit the action of bacteria by refrigeration, and reduce the tendency of molds to form by the combined action of refrigeration and evacuation of oxygen contained in the air.

It is an object of the present invention to provide substantially complete protection to perishable materials by treating them with a combination of ultra violet light, refrigeration, removing the oxygen from the chamber by evacuation, and providing the proper humidity.

Another object of the invention is to provide an apparatus for preservation oi' perishable material by removing oxygen from the chamber in which it is stored and sterilizing the material by ultra violet light.

Other and incidental objects of the invention will be apparent from the reading of the following specification and from .the inspection of. the accompanying drawings in which:

Figure l is a vertical cross section of the stor-' age chamber, which may be placed in a refrigerator;

Figure 2 is a. vertical cross section of a refrigerator with a storage compartment mounted therein; I

Figure 8 is a horizontal cross section of the storage compartment indicating the wiring diaram of the ultra violet lamp; I

Figure 4 is a schematic diagram of the electrical connections of the vacuum pump;

Figure 5 is a longitudinal section of one type of latch for the door of the unit;

Figure 6- is a schematic diagram of a modificationof the wiring of the ultra violet light source including a thermostatic switch to start the arc; and

Figure 7 is a schematic diagram of a modification of Figure 6 showing means thermostatically to controlthe periods of operation of the ultra violetsource.

Referring first to Figure l, the storage compartment is generally indicated at l 0. This chamber is appropriately constructed so as to withstand the vacuum therein to approximately the vapor pressure 01' water at the temperature at which the materials areto be preserved. The chamber 10 is provided with a door 22 which is sealed to the chamber by resilient member 23.

I The door is provided with the usual hinges 32 and latch 33, Fig. 3. A vacuum pump 3| for evacuating the chamber is provided. Thi is preferably driven by an electric motor 30-controlled as hereinafter described. The motor 30 is housed in an enclosure ll. Electrical conductors are led into the enclosure ll through a conduit 30a. The pipe I1 is provided so that air exhausted from the chamber may be carried to the exterior of the refrigerator, Fig. 2. In the chamber there is provided an appropriate source of ultra violet light i2 in such a position that its rays are direfrigerator. This chamber is preferably spaced away from the refrigerator walls as indicated at It so that the cool air may circulate around all sides or the chamber in order to provide conductive refrigeration through the walls of the container, in contradistinction to the usual refrigeration by convection o1 currents of air. The chamber may be provided with shelves it of such material that they will conductheat from the material stored thereon to the conductive walls of the chamber.

In Figure 4 the upper surface of the storage unit is indicated at I0 and mounted thereon is the motor 30 connected to a vacuum pump 3|. The vacuum pump is connected to the interior of the storage unit through an appropriate pipe I1 and exhausts to the air through a second pipe I1. The motor and the pump are separated from the interior of the refrigerator by an appropriate heat insulating layer. The vacuum pump 3i may be either directly connected to the exterior atmosphere, or it may exhaust into the enclosure ii through a pipe i1 and the exhaust be carried to the exterior atmosphere by a pipe H, as indicated in Figure 2. The latter construction has the advantage that the motor is cooled by the air exhausted from the compartment iii. In order to control the air pressure in the compartment iii, a pressure responsive means I I8 is provided. This means controls the contacts H9,

and when a sufllciently low pressure in the unit i0 is reached, these contacts are opened and the motor 30' is turned oif. An appropriate check 3 valve I42 is provided to retain the vacuum in the compartment I3.

The door 22 must be capable of sealing the unit I3 sufliciently securely to maintain the vacuum therein but at the same time it must be capable of being readily opened. In the opening process it must be able to turn off the vacuum pump and break the vacuum. In order to accomplish this, I have devised novel securing means and a vacuum breaking means for the door 22. Referring to Figure 5, the door 22 is secured against the body of the unit I3 with an airtight seal by the gasket I34 extending completely around the door 22. The door is latched in its closed condition by a bolt I33 sliding into an appropriate aperture in the portion I3. This bolt I33 may be opened by the handle 33 which operates a slide I3I connected to the bolt I33 as will be hereinafter described. In order to break the vacuum so that the door 22 may be opened, the slide I3I is provided with a valve member I32 which cooperates with a barrel member or sleeve I33 which is installed in a vacuum tight manner in the door 22. When the handle 33 is rotated clockwise, the member I3I will be moved to the right against the pressure of the spring I43. The valve I32 will be lifted from the barrel I33 and air will be permitted to enter the body of the unit through the apertures I31.

The valve I32 is connected to the member I3I through a longitudinally expansible metal tube I33 so that after the valve I32 is sealed the member I 3i and the latch I33 may be moved forward by the springs I33 and I43 until the member I33 is firmly seated. When the door is closed and the member I33 is seated, the latch I33 extends past spring contacts I2 I, and closes the circuit through the motor 33 again evacuating the storage unit. Conversely, when the door 22 is to be opened, the handle 33 is rotated clockwise, the latch I33 is withdrawn, the contacts I2I are separated, turning of! the motor 33 and the vacuum pump 3 I, and the valve I32 is then raised permitting the entrance of air to the compartment and permitting the opening of the door 22.

The lamp I2 shown is one of the many types of ultra violet sources. Any other suitable source such as a mercury vapor are enclosed in suitable glass and having an auxiliary unit containing transformers and reactors, or rectifiers, or suitably enclosed incandescent carbon filaments may be used. One suitable mercury vapor lamp employing an ordinary fluorescent light fixture and auxiliaries is marketed by the General Electric Company under the trade name "Uviarc.

The lamp shown in Figure 3 is one type of ultra violet sterilizing lamp. This lamp I2 includes a tube of a glass, capableof transmitting ultra violet light, and enclosing vapors which are rendered radiating by the passage of electric current therethrough. The starting electrodes 33 of the lamp are formed of coil heating elements analogous to the filaments of electric light bulbs. The lamp may be started by connecting the terminal of one of the electrodes to a conductor of a 110 volt circuit and the terminal of the other electrode throuzh a ballast reactance 31 to the other terminal of the 110 volt circuit. When the two terminals of the electrodes are bridged by a conductor. a heating current will flow through each of the electrodes in series and the lam will light on breaking of the bridging connection. The current will then flow from one electrode to the other through vapor in the lamp.

To insure that the sterilizin lamp will not burn when door 22 is opened. that the lampwill burn a 'for a desired interval immediately after closing the door, and that the light will burn for desired periods of time at desired intervals independently of its activation by the door. a time delay device 23, an interval timer 33 and suitable electrical connections are provided.

When the door is opened, the starting of the lamp is prevented by a switch 43 which interrupts the supply circuit when the door 22 is open, and completes the circuit when the door is closed. On the closing of the door the switch 43 is closed and the time delay device 23 is started by the operation of the arm 33 connected to the operating pin of the switch 43. The cam of the time delay device 23 operates in a counter-clockwise direction, first closing the switch 23. Thereupon the electrodes 33 are heated by the flow of current in the circuit extending through the reactor 31, the upper electrode 33, the conductor 33, the switch 23, the conductor 33, lower electrode 33, switch 44, conductor 43, switch 4i, conductor 42, switch 43 and conductor 43.

It should be noted that the time delay device 23 and the interval timer 33 each operates two switches 23 and H, and 43 and 44, respectively, of which the starting switch 23 or 43 is closed for a brief interval and the stopping switch H or 44, respectively, is opened for a brief interval, in sequence. These results may be accomplished in diflerent known fashions, as will be readily understood by those versed in the art, the drawings being intended merely to show diagrammatically the principle of operation of the device.

After an interval sumcient to heat the electrodes 33, the cam 43 of the time delay device permits the switch '23 to open, thereby opening the shunt circuit around the tube I2. Opening of the circuit will, because of the reactor 31, cause a momentary high potential to be established across the tube [2, which establishes an arc across the electrodes. The circuit then includes the reactor 31, upper and lower electrodes 33, the switch 44, the conductor 43, the switch M, the conductor 42, switch 43 and conductor 43. After the lamp has been on for the required time, determined by the time delay device 23, the cam 43 opens switch 4I and extinguishes the lamp.

The interval timer 33 operates independently of the time delay device 23. The starting switch for the interval timer is indicated at 43 and operates in the same general manner as the switch 23 in the time delay device. The cam of the interval timer 33 isglikewise indicated as operating in a counter-clockwise direction. When the switch 43 is closed, the starting circuit is completed through the reactor 31, the upper electrode 33, conductor 41, switch 43, conductor 33, lower electrode 33, switch 44, conductor 43, switch 4|. conductor 42, switch 43 and the conductor 43. After an interval sufllcient to heat the electrodes, the cam 43 of the interval timer permits the switch 43 to open, and the current then flows through the circuit including the reactor 31, upper and lower electrodes 33, switch 44, conductor 43, switch 4|, conductor 42, switch 43, and conductor 43, as before. The arc is extinguished when the cam 43 opens the switch 44, or when the switch 43 is opened by opening the door.

As before mentioned, the period of closure of the switches 23 and 43 is of sumcient duration to heat the electrodes 33 to the point where the vapor contained in the tube 34 can carry the current. The opening and closing of switches 4I and 44, however. occurs very quickly and a there is, therefore, no detrimental interaction between the controlling means. -T'h'e period of opening or the switches 4| and 44 should be great enough to permit the heated electrodes 36 to cool enough so that the arc will not immediately be reestablished on their reclosure.

The operation of the device of my invention may now be summarized briefly as follows: When the door of chamber I0 is opened by means of handle 33, the vacuum in the'ch'amber is broken by the opening of valve I32, and the vacuum pump 3| is rendered inoperative by the opening of contacts |'2|. Upon reclosing of the door after, for example, a comestible article has been placed in the chamber ill, the bolt 33. latches the door in sealing position and the vacuum pump is rendered operative by closing of contacts |2l. vacuum pump continues to operate until the desired degree of vacuum is obtained, at which point the bellows 8 stop further operation of the pump by opening of contacts H9. In the meantime, the ultraviolet light source ..|2 has The ' It will be noted that whenever-the door 22 stands open, contact 43 remains open so that lamp I2 is prevented from operating. The timers 36 and 26 may be driven by clockwork or by electric a portion of the current which actuates the lamp also commenced to function. When the door 22 was closed, switch 43 was closed and the arm 80 started operation of the time delay device 26, the cam 46 of this device serving to close switch 25, so that with both switches 43 and 25 closed, the circuit for heating the electrodes 35 is established for the proper interval of time to permit' .the electrodes 35 to heat.

At the end of this interval of time, switch 25 reopens due to the action of the cam 46, and through the action of the reactor 31 a high voltage is produced starting the operation of the tube 2. This operation now continue for a desired period of time. the duration of this period being governed by the interval of time required by the cam 46 to continue its counter-clockwise rotation to the point at which it opens switch 4|. When this switch is opened, the tube 2 ceases to act. This interval is arbitrarily chosen to be of such duration that under normal conditions the air within the chamber and the exterior of the comestibles contained therein have been sterilized to a desired degree. Cam 46, however, continues its rotation until switch 4| again closes, but'the tube |2 does not become reenergized by closing oi! switch 4|, by reason of the fact that electrodes 35 have cooled off sufliciently to prevent the reestablishment of the circuit of the are between electrodes 35, even though 110 volts potential is applied across these electrodes. Moreover, the starting circuit of the tube is open at contact 25, for the reason that the cam 46 of the time delay device 26 ceases its rotation upon its return to the starting position indicated in Fig. 3.

The purpose of interval timer 36 is to set the tube 2 into operation intermittently for given periods of time to bring about resterilization of the contents. The timer 36 rotates its cam 49 continuously in counterclockwise direction. When the cam closes the switch 48 the starting circuit of tube I2 is completed, causing the tube to commence operation. When the cam reaches contact 44 and opens the same, the operation of the tube is interrupted. It remains so interrupted until the contact 48 is again reclosed.

The circuits of the present invention. therefore, serve to bring about operation of the ultra violet radiation, both at the time of closing of the door of the chamber and at regular intervals thereafter. It will be understood, of course, that the durations of these intervals and of the periods of energization of the tube may be made such as desired.

Figures 6 and 7 show modifications of the circuit using such bi-metallic strips controlled by resistance elements. In Figure 5 the switch 43 is controlled by'the door as in Figure 3 and the time delay device62 functions in the same manner as the time delay device 26 in Figure 3, and the interval timer 64 performs function as the interval timer 36. The important difl'erence in the operation of this circuit as distinguished from the circuit in Figure 3 is the manner of establishing the arc across tube In this case the electrodes 35a are connected to a switch 6| around which is shunted resistor 58. When the circuit is closed by the closing of the door and the consequent closing of the switch 43, current flows through a resisto 68 which closes the bimetallic switch 6|. Closing of switch 6| shunts out the resistor 58 which thereupon becomes cool and allows the switch 6| to open again. When the switch 6| opens, the reactor 31a causes an arc to be established across the electrodes 36a and the lamp continues to burn until extinguished by the interruption of the supply circuit by the switch 44. The resistance 58 is so high in relation to the voltage drop across the are that after the arc is established there is no appreciable current through the resistor 58 and therefore the switch 6| does not close again.

The cam 63 in the timer 62 rotates three-quarters of a revolution until the switch 44 is held open where it remains until the door is again opened. Thereafter the lamp i2 continues to functionunder the control of the interval timer 64 controlling switch 65. The switch 6i functions in the manner above described upon each operation 01. switch 65.

In the circuit shown in Figure 7, a thermostatic switch FL is substituted for both the time delay device 62 and the interval timer 64, the circuit otherwise remaining the same. In this modification the thermostatic switch FL is controlled by a resistor R in the same manner as in the well known thermostatic lamp flashers. When the switch 43 is opened no current passes through the resistor R and the switch FL is closed. When the switch 43 is closed, current passes through. the resistor R, through the choke 31a, through the resistor 56, etc. The switch 6| establishes the are as before to cause actuation of the tube I2. Resistor R, meanwhile, heats the bi-metallic strip in the switch FL at a rate dependent on the desired length of the period of actuation of the tube l2. When the strip is sufiiciently heated it shown. but what I desire to cover by Letters Patent'is set forth in the appended claims.

I claim:

1. A storage chamber adapted to be refrigerated including a removable airtight box capable oi withstanding external air pressure, a door ior sealing said box, means mounted on the box for evacuating said box to a predetermined low pressure, means for producing ultra violet light within said box, and humidifying means within said box.

2. A storage chamber adapted to be refrigerated including a removable airtight thermally conductive box capable of withstanding external air pressure, a door for sealing said box, means mounted on the box for evacuating said box to a predetermined low pressure, means for producing ultra violet light-within said box, and humidifying means within said box.

3. A storage chamber adapted to be refrigerated including a removable airtight thermally conductive box capable of withstanding external air pressure, a door for sealing said box, means mounted on the box for evacuating said box to a predetermined low pressure, means mounted on the box for producing ultra violet light within said box, humidifying means within said box, and thermally conductive shelves within said box connected to the walls thereof.

4. In combination, a refrigerator, a removable airtight thermally conductive box therein capable oi withstanding external air pressure, a door for sealing said box, means mounted on the box for evacuating said box to a predetermined low pressure, means for producing ultra violet light within said box, and humidifying means within said box.

5. In combination, a refrigerator, a removable airtight thermally conductive box therein capable of withstanding external air pressure, a door for sealing said box, means mounted on the box for evacuating said box to a predetermined low pressure, means for producing ultra violet light within said box, humidifying means within said box, and means for controlling the source of ultra violet radiation.

6. In combination, a reirigerator, a removable air tight thermally conductive box therein capable oi withstanding external air pressure, a door for sealing said box, means mounted on the box for evacuating said box to a predetermined low pressure, means for producing ultra violet light within said box, and means on the box for controlling the source of ultra violet radiation including a switch adapted to be operated by the door of said chamber for turning of! said source when the door is open, an interval timer switch connected between the door switch and said source to turn said source on at regular intervals for regular times, and a time delay switch connected in series with the door operated switch and in parallel with the interval timer to turn said source on for a limited time immediately after closing or the door.

WILLIAM L. MAXSON.

REFERENCES CITED The following references are of recordin the Idle 0! this patent:

UNITED STATES PATENTS Number Name Date 2,107,763 Potter Feb. 8, 1938 2,109,002 Warren Feb. 22, 1938 2,145,196 Biggs Jan. 24, 1939 2,263,456 Darcy Nov. 18, 1941 2,246,676 Hainsworth June 24, 1941 2,234,254 Hull Mar. 11, 1941 FOREIGN PATENTS Number Country Date 521,040 Germany Mar. 18, 1931 

